The candidate is presently a resident in the Pathology Department at the Massachusetts General Hospital and has a strong research and clinical interest in bacterial pathogens. He spent two years at the National Institutes of Health learning bacterial genetics, and in elective time this year, is studying Listeria and Salmonella pathogenesis at the Whitehead Institute. The candidate's career development plan will be under the mentorship of Ralph Isberg, Ph.D., in the Molecular Biology and Microbiology Department at Tufts University School of Medicine. This department has a strong microbial pathogenesis group and has extensive interactions with the Infectious Disease Department at New England Medical Center. The candidate's immediate career goal is to acquire skills necessary for independent study of pathogen host interactions. During his career development plan, he will, therefore, take course work to expand his knowledge of bacterial pathogenesis and related disciplines of cell biology and immunology. In the research project, he will study virulence mechanisms of Leqionella pneumophila, a cause of severe pneumonia and a model for pathogens that survive and replicate inside phagocytic vacuoles. An animal model will be used to identify virulence mutants that fail to survive during the course of infection. Assays of the host immune response and bacterial survival during infection will be used to rapidly categorize virulence mutants and plan further experiments to define virulence gene function. The candidate's long term career goal is to become an independent bacterial pathogenesis researcher associated with an academic pathology department.